SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES | SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES PRINCIPLES OF CONSOLIDATION – The operating activities of subsidiaries are included in the accompanying consolidated financial statements (“financial statements”) from the date of acquisition. Investments in companies in which we have the ability to exercise significant influence, but not control, are accounted for by the equity method. All intercompany transactions and balances, with our consolidated entities and the unsettled amount of intercompany transactions with our equity method investees, have been eliminated in consolidation. As stated in Note 1 above, the BRMG and NY Groups are variable interest entities and we consolidate the operating activities and balance sheets of each. Additionally, we determined that our unconsolidated joint venture, ScriptSender, LLC, is also a VIE as it is dependent on our operational funding but we are not a primary beneficiary since RadNet does not have the power to direct the activities of the entity that most significantly impact the entity’s economic performance. See Investment in Joint Ventures section of Note 2 for further explanation. USE OF ESTIMATES - The financial statements were prepared in accordance with U.S. generally accepted accounting principles (GAAP), which requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. These estimates and assumptions affect various matters, including our reported amounts of assets and liabilities in our consolidated balance sheets at the dates of the financial statements; our disclosure of contingent assets and liabilities at the dates of the financial statements; and our reported amounts of revenues and expenses in our consolidated statements of operations during the reporting periods. These estimates involve judgments with respect to numerous factors that are difficult to predict and are beyond management’s control. As a result, actual amounts could materially differ from these estimates. RECLASSIFICATION – We have reclassified certain amounts within net service fee revenue for 2017 and 2016 to conform to our 2018 presentation. REVENUES – On January 1, 2018, the Company adopted the new revenue recognition accounting standard issued by the Financial Accounting Standards Board (“FASB”) and codified in the ASC as topic 606 (“ASC 606”). The revenue recognition standard in ASC 606 outlines a single comprehensive model for recognizing revenue as performance obligations, defined in a contract with a customer as goods or services transferred to the customer in exchange for consideration, are satisfied. The standard also requires expanded disclosures regarding the Company’s revenue recognition policies and significant judgments employed in the determination of revenue. The Company applied the modified retrospective approach to all contracts when adopting ASC 606. As a result, at the adoption of ASC 606 the majority of what was previously classified as the provision for bad debts in the statement of operations are now reflected as implicit price concessions (as defined in ASC 606) and therefore included as a reduction to net operating revenues in 2018. For changes in credit issues not assessed at the date of service, the Company will prospectively recognize those amounts in other operating expenses on the statement of operations. For periods prior to the adoption of ASC 606, the provision for bad debts has been presented consistent with the previous revenue recognition standards that required it to be presented separately as a component of net operating revenues. At December 31, 2017 we had recorded approximately $ 34.6 million of allowance for doubtful accounts. As part of the adoption of ASC 606 this amount was reclassified to be a component of net patient accounts receivable. Other than these changes in presentation on the consolidated statement of operations and consolidated balance sheet, the adoption of ASC 606 did not have a material impact on the consolidated results of operations for the twelve months ended December 31, 2018. Our revenues generally relate to net patient fees received from various payers and patients themselves under contracts in which our performance obligations are to provide diagnostic services to the patients. Revenues are recorded during the period our obligations to provide diagnostic services are satisfied. Our performance obligations for diagnostic services are generally satisfied over a period of less than one day. The contractual relationships with patients, in most cases, also involve a third-party payer (Medicare, Medicaid, managed care health plans and commercial insurance companies, including plans offered through the health insurance exchanges) and the transaction prices for the services provided are dependent upon the terms provided by (Medicare and Medicaid) or negotiated with (managed care health plans and commercial insurance companies) the third-party payers. The payment arrangements with third-party payers for the services we provide to the related patients typically specify payments at amounts less than our standard charges and generally provide for payments based upon predetermined rates per diagnostic services or discounted fee-for-service rates. Management continually reviews the contractual estimation process to consider and incorporate updates to laws and regulations and the frequent changes in managed care contractual terms resulting from contract renegotiations and renewals. As it relates to BRMG centers, this service fee revenue includes payments for both the professional medical interpretation revenue recognized by BRMG as well as the payment for all other aspects related to our providing the imaging services, for which we earn management fees from BRMG. As it relates to non-BRMG centers, this service fee revenue is earned through providing the use of our diagnostic imaging equipment and the provision of technical services as well as providing administration services such as clerical and administrative personnel, bookkeeping and accounting services, billing and collection, provision of medical and office supplies, secretarial, reception and transcription services, maintenance of medical records, and advertising, marketing and promotional activities. Our revenues are based upon the estimated amounts we expect to be entitled to receive from patients and third-party payers. Estimates of contractual allowances under managed care and commercial insurance plans are based upon the payment terms specified in the related contractual agreements. Revenues related to uninsured patients and uninsured copayment and deductible amounts for patients who have health care coverage may have discounts applied (uninsured discounts and contractual discounts). We also record estimated implicit price concessions (based primarily on historical collection experience) related to uninsured accounts to record self-pay revenues at the estimated amounts we expect to collect. As part of the adoption of ASC 606, the Company elected two of the available practical expedients provided for in the standard. First, the Company did not adjust the transaction price for any financing components as those were deemed to be insignificant. Additionally, the Company expensed all incremental customer contract acquisition costs as incurred as such costs are not material and would be amortized over a period less than one year. Under capitation arrangements with various health plans, we earn a per-enrollee amount each month for making available diagnostic imaging services to all plan enrollees under the capitation arrangement. Revenue under capitation arrangements is recognized in the period in which we are obligated to provide services to plan enrollees under contracts with various health plans. The Company’s total net revenues for the years ended December 31, are presented in the table below based on an allocation of the estimated transaction price with the patient between the primary patient classification of insurance coverage. 2018 2017 2016 Commercial insurance $ 542,011 $ 534,224 $ 515,150 Medicare 192,881 179,678 173,262 Medicaid 25,615 24,133 23,272 Workers' compensation/personal injury 34,193 32,969 31,791 Other patient revenue 25,117 29,882 28,815 Management fee revenue 13,882 13,127 11,868 Imaging on call and software 16,261 18,116 19,462 Other 18,781 25,049 17,967 Service fee revenue, net of contractual allowances and discounts 868,741 857,178 821,587 Provision for bad debts – (46,555 ) (45,387 ) Net service fee revenue 868,741 810,623 776,200 Revenue under capitation arrangements 106,405 111,563 108,335 Total net revenue $ 975,146 $ 922,186 $ 884,535 ACCOUNTS RECEIVABLE – Substantially all of our accounts receivable are due under fee-for-service contracts from third party payors, such as insurance companies and government-sponsored healthcare programs, or directly from patients. We continuously monitor collections from our payors and record an estimated price concession based upon specific payor collection issues that we have identified and our historical experience. We have entered into factoring agreements with various institutions and sold certain accounts receivable under non-recourse agreements. These transactions are accounted for as a reduction in accounts receivable as the agreements transfer effective control over and risk related to the receivables to the buyers. The aggregate gross amount factored under these facilities was $20.5 million for the year ended December 31, 2018 and the cost of factoring such accounts receivable for the year ended December 31, 2018 was $440,000 . Proceeds will be received as a combination of cash and payments on notes receivable and will be reflected as operating activities on our statement of cash flows and on our balance sheet as prepaid expenses and other current assets for the current portion and deposits and other for the long term portion. At December 31, 2018 we have $18.6 million remaining to be collected on these agreements. We do not utilize factoring arrangements as an integral part of our financing for working capital. MEANINGFUL USE INCENTIVE – Under the American Recovery and Reinvestment Act of 2009, a program was enacted that provides financial incentives for providers that successfully implement and utilize electronic health record technology to improve patient care. Our software development team in Canada developed a Radiology Information System (RIS) software platform that has been awarded meaningful use certification. As this certified RIS system is implemented throughout our imaging centers, the radiologists that utilize this software can be eligible for the available financial incentives. In order to receive such incentive payments, providers must attest that they have demonstrated meaningful use of the certified RIS in each stage of the program. We accounted for this meaningful use incentive under the Gain Contingency Model outlined in ASC 450-30, and recorded the meaningful use incentive within non-operating income only after Medicare accepts an attestation from the qualified eligible professional demonstrating meaningful use. The program ended in 2017 and we recorded approximately $250,000 and $2.8 million during the twelve months ended December 31, 2017 and 2016 , respectively, relating to this incentive. GAIN ON RETURN OF COMMON STOCK – In the second quarter of 2016, we determined that certain pre-acquisition financial information of Diagnostic Imaging Group (“DIG”) provided to us by the sellers contained errors. As a result of this, we negotiated and reached a settlement with the sellers of DIG in June 2016 for the return of 958,536 shares of common stock which had a fair value of $5.0 million on the date of return. Such return has been recognized as a gain on return of common stock in our statement of operations. SOFTWARE REVENUE RECOGNITION – Our subsidiary, eRAD, Inc., sells Picture Archiving Communications Systems (“PACS”) and related services, primarily in the United States. The PACS systems sold by eRAD are primarily composed of certain elements: hardware, software, installation and training, and support. Sales are made primarily through eRAD’s sales force and generally include hardware, software, installation, training and first-year warranty support. Hardware, which is not unique or special purpose, is purchased from a third-party and resold to eRAD’s customers with a small mark-up. We have determined that our core software products, such as PACS, are essential to most of our arrangements as hardware, software and related services are sold as an integrated package. These transactions are accounted for under ASC 606, Revenue from contracts with customers . Under this method, revenue is recognized when a performance obligation is satisfied by transferring a promised good or service to a customer. For the years ended December 31, 2018 , 2017 and 2016 , we recorded approximately $6.8 million, $6.1 million , and $6.2 million , respectively, in revenue related to our eRAD business which is included in net service fee revenue in our consolidated statement of operations. At December 31, 2018 we had a deferred revenue liability of approximately $2.3 million associated with eRAD sales which we expect to recognize into revenue over the next 12 months. SOFTWARE DEVELOPMENT COSTS – Costs related to the research and development of new software products and enhancements to existing software products all for resale to our customers are expensed as incurred. We utilize a variety of computerized information systems in the day to day operation of our diagnostic imaging facilities. One such system is our front desk patient tracking system or Radiology Information System (“RIS”). We have historically utilized third party RIS software solutions and pay monthly fees to outside third party software vendors for the use of this software. We have developed our own RIS solution through our wholly owned subsidiary, Radnet Management Information Systems (“RMIS”) and began utilizing this system beginning in the first quarter of 2015. In accordance with ASC 350-40, Accounting for the Costs of Computer Software Developed for Internal Use, the costs incurred by RMIS toward the development of our RIS system, which began in August, 2010 and continued until December 2014, were capitalized and are being amortized over its useful life which we determined to be 5 years . Total costs capitalized were approximately $6.4 million . We began recording amortization of $107,000 per month for our use of this software in January 2015. We have entered into multiple agreements to license our RIS system to outside customers. For the twelve months December 31, 2018 and December 31, 2017 , we received approximately $248,000 and $492,000 with respect to this licensing agreement, respectively. In accordance with ASC 350-40, we recorded the receipt of these funds against the capitalized software costs explained above. As a result of the combination of amortization and sales under multiple license agreements, as of December 31, 2018, our Software Development Costs are fully amortized. CONCENTRATION OF CREDIT RISKS – Financial instruments that potentially subject us to credit risk are primarily cash equivalents and accounts receivable. We have placed our cash and cash equivalents with one major financial institution. At times, the cash in the financial institution is temporarily in excess of the amount insured by the Federal Deposit Insurance Corporation, or FDIC. Substantially all of our accounts receivable are due under fee-for-service contracts from third party payors, such as insurance companies and government-sponsored healthcare programs, or directly from patients. We continuously monitor collections and maintain an allowance for bad debts based upon our historical collection experience. CASH AND CASH EQUIVALENTS – We consider all highly liquid investments that mature in three months or less when purchased to be cash equivalents. The carrying amount of cash and cash equivalents approximates their fair market value. DEFERRED FINANCING COSTS – Costs of financing are deferred and amortized using the effective interest rate method. Deferred financing costs are solely related to our Revolving Credit Facilities. In connection with our assumption of operational control of the New Jersey Imaging Networks as of October 1, 2018, the Company currently has two separate revolving lines of credit from different lending institutions, Barlays and SunTrust. However, only the Barclays revolving line of credit has deferred financing costs associated with the lending agreement. Deferred financing costs, net of accumulated amortization, were $1.4 million and $1.9 million for the twelve months ended December 31,2018 and 2017, respectively. In conjunction with our Fourth Amendment and Fifth Amendment to our First Lien Credit Agreement from Barclays, a net addition of approximately $371,000 was added to deferred financing costs for the twelve months ended December 31, 2017. See Note 8, Revolving Credit Facility, Notes Payable, and Capital Leases for more information on our Revolving Lines of Credit. INVENTORIES – Inventories, consisting mainly of medical supplies, are stated at the lower of cost or net realizable value with cost determined by the first-in, first-out method. PROPERTY AND EQUIPMENT – Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization of property and equipment are provided using the straight-line method over the estimated useful lives, which range from 3 to 15 years . Leasehold improvements are amortized at the lesser of lease term or their estimated useful lives, which range from 3 to 30 years . Maintenance and repairs are charged to expense as incurred. BUSINESS COMBINATION – In January 2017, the FASB issued ASU No. 2017-01 (“ASU 2017-01”), Clarifying the Definition of a Business . The update provides a framework for evaluating whether a transaction should be accounted for as an acquisition and/or disposal of a business versus assets. In order for a purchase to be considered an acquisition of a business, and receive business combination accounting treatment, the set of transferred assets and activities must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. If substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, then the set of transferred assets and activities is not a business. We first evaluate all purchases under this framework. Once the purchase has been determined to be the acquisition of a business, we are required to recognize separately from goodwill the assets acquired and the liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred over the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While we use our best estimates and assumptions to accurately value assets acquired and liabilities assumed at the acquisition date, our estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, we record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to our consolidated statements of operations. GOODWILL AND INDEFINITE LIVED INTANGIBLES – Goodwill at December 31, 2018 totaled $418.1 million and $256.8 million at December 31, 2017. Indefinite lived intangible assets at December 31, 2018 were $9.8 million and at December 31, 2017 totaled $7.9 million and are associated with the value of certain trade name intangibles. Goodwill and trade name intangibles are recorded as a result of business combinations. When we determine the carrying value of goodwill exceeds its fair value an impairment charge would be recognized and should not exceed the total amount of goodwill allocated to that reporting unit. We determined fair values for each of the reporting units using the market approach, when available and appropriate, or the income approach, or a combination of both. We assess the valuation methodology based upon the relevance and availability of the data at the time we perform the valuation. If multiple valuation methodologies are used, the results are weighted appropriately.Our Teleradiology unit, Imaging On Call, (IOC), experienced a reduction of professional medical group clients and a loss of a contract with a major local health provider during 2018. This affected its estimated fair value and resulted in impairment charges to our reporting unit of $3.9 million for the twelve months ended December 31, 2018 , with goodwill representing $3.8 million of the total and the remainder being its trade name of approximately $100,000 . The estimated fair value of IOC reporting unit was determined by using the discounted cash flow method. LONG-LIVED ASSETS – We evaluate our long-lived assets (property and equipment) and intangibles, other than goodwill, for impairment when events or changes indicate the carrying amount of an asset may not be recoverable. U.S. GAAP requires that if the sum of the undiscounted expected future cash flows from a long-lived asset or definite-lived intangible is less than the carrying value of that asset, an asset impairment charge must be recognized. The amount of the impairment charge is calculated as the excess of the asset’s carrying value over its fair value, which generally represents the discounted future cash flows from that asset or in the case of assets we expect to sell, at fair value less costs to sell. We determined that there were no events or changes in circumstances that indicated our long-lived assets were impaired during any periods presented. INCOME TAXES – Income tax expense is computed using an asset and liability method and using expected annual effective tax rates. Under this method, deferred income tax assets and liabilities result from temporary differences in the financial reporting bases and the income tax reporting bases of assets and liabilities. The measurement of deferred tax assets is reduced, if necessary, by the amount of any tax benefit that, based on available evidence, is not expected to be realized. When it appears more likely than not that deferred taxes will not be realized, a valuation allowance is recorded to reduce the deferred tax asset to its estimated realizable value. For net deferred tax assets we consider estimates of future taxable income in determining whether our net deferred tax assets are more likely than not to be realized. Income taxes are further explained in Note 10. UNINSURED RISKS – On November 1, 2008 we obtained a fully funded and insured workers’ compensation policy, thereby eliminating any uninsured risks for employee injuries occurring on or after that date. This fully funded policy remained in effect through November 1, 2013 and continues to cover any claims incurred through this date. On November 1, 2013 we entered into a high-deductible workers’ compensation insurance policy. We have recorded liabilities of $2.8 million for each of the years ending December 31, 2018 and December 31, 2017 , respectively, for the estimated future cash obligations associated with the unpaid portion of the workers compensation claims incurred. We and our affiliated physicians carry an annual medical malpractice insurance policy that protects us for claims that are filed during the policy year and that fall within policy limits. The policy has a deductible for which is $10,000 per incidence for the years ending December 31, 2018 and December 31, 2017 , respectively. In December 2008, in order to eliminate the exposure for claims not reported during the regular malpractice policy period, we purchased a medical malpractice tail policy, which provides coverage for any claims reported in the event that our medical malpractice policy expires. As of December 31, 2018 , this policy remains in effect. We have entered into an arrangement with Blue Shield to administer and process claims under a self-insured plan that provides health insurance coverage for our employees and dependents. We have recorded liabilities as of December 31, 2018 and 2017 of $4.8 million and $4.5 million , respectively, for the estimated future cash obligations associated with the unpaid portion of the medical and dental claims incurred by our participants. Additionally, we entered into an agreement with Blue Shield for a stop loss policy that provides coverage for any claims that exceed $250,000 up to a maximum of $1.0 million in order for us to limit our exposure for unusual or catastrophic claims. LOSS AND OTHER UNFAVORABLE CONTRACTS – We assess the profitability of our contracts to provide management services to our contracted physician groups and identify those contracts where current operating results or forecasts indicate probable future losses. Anticipated future revenue is compared to anticipated costs. If the anticipated future cost exceeds the revenue, a loss contract accrual is recorded. In connection with the acquisition of Radiologix in November 2006, we acquired certain management service agreements for which forecasted costs exceeds forecasted revenue. As such, an $8.9 million loss contract accrual was established in purchase accounting, and is included in other non-current liabilities. The recorded loss contract accrual is being accreted into operations over the remaining term of the acquired management service agreements, which ends in 2031. As of December 31, 2018 and 2017 , the remaining accrual balance is $4.6 million and $5.0 million , respectively. In addition and related to acquisition activity, we have certain operating lease commitments for facilities where the fair market rent differs from the lease contract rate. We have recorded an unfavorable contract liability representing the difference between the total value of the fair market rent and the contract rent over the current term of the lease applicable from the date of acquisition. As of December 31, 2018 and 2017, the unfavorable contract liability on these leases is $2.2 million and $1.4 million respectively. EQUITY BASED COMPENSATION – We have one long-term incentive plan that we adopted in 2006 and which we first amended and restated as of April 20, 2015, and again on March 9, 2017 (the “Restated Plan”). The Restated Plan was approved by our stockholders at our annual stockholders meeting on June 8, 2017. We have reserved for issuance under the Restated Plan 14,000,000 shares of common stock. We can issue options, stock awards, stock appreciation rights, stock units and cash awards under the Restated Plan. Certain options granted under the Restated Plan to employees are intended to qualify as incentive stock options under existing tax regulations. Stock options and warrants generally vest over three to five years and expire five to ten years from date of grant. The compensation expense recognized for all equity-based awards is recognized over the awards’ service periods. Equity-based compensation is classified in operating expenses within the same line item as the majority of the cash compensation paid to employees. See Note 11 Stock-Based Compensation for more information. FOREIGN CURRENCY TRANSLATION – The functional currency of our foreign subsidiaries is the local currency. In accordance with ASC 830, Foreign Currency Matters , assets and liabilities denominated in foreign currencies are translated using the exchange rate at the balance sheet dates. Revenues and expenses are translated using average exchange rates prevailing during the reporting period. Any translation adjustments resulting from this process are shown separately as a component of accumulated other comprehensive income (loss). Foreign currency transaction gains and losses are included in the determination of net income. COMPREHENSIVE INCOME (LOSS) – ASC 220, Comprehensive Income, establishes rules for reporting and displaying comprehensive income (loss) and its components. Our unrealized gains or losses on foreign currency translation adjustments and our interest rate cap agreement are included in comprehensive income (loss). The components of comprehensive income (loss) for the three years in the period ended December 31, 2018 are included in the consolidated statements of comprehensive income (loss). DERIVATIVE INSTRUMENTS – In the fourth quarter of 2016, we entered into two forward interest rate cap agreements ("2016 Caps"). The 2016 Caps will mature in September and October 2020. The 2016 Caps had notional amounts of $150,000,000 and $350,000,000 , respectively, which were designated at inception as cash flow hedges of future cash interest payments associated with portions of our variable rate bank debt. Under these arrangements, we purchased a cap on 3 month LIBOR at 2.0% . We are liable for a $5.3 million premium to enter into the caps which is being accrued over the life of the 2016 Caps. At inception, we designated our 2016 Caps as cash flow hedges of floating-rate borrowings. In accordance with ASC Topic 815, derivatives that have been designated and qualify as cash flow hedging instruments are reported at fair value. The gain or loss of the hedge (i.e. change in fair value) is reported as a component of accumulated other comprehensive income in the consolidated statement of equity. See Fair Value Measurements section below for the fair value of the 2016 Caps at December 31, 2018 . A tabular presentation of the effect of derivative instruments on our consolidated statement of comprehensive income (loss), net of taxes is as follows (amounts in thousands): For the twelve months ended December 31, 2018 Effective Interest Rate Cap Amount of Gain Recognized on Derivative Location of Gain Recognized in Income on Derivative Interest rate contracts $2,876 Other Comprehensive Income For the twelve months ended December 31, 2017 Effective Interest Rate Cap Amount of Loss Recognized on Derivative Location of Loss Recognized in Income on Derivative Interest rate contracts (880) Other Comprehensive Loss For the twelve months ended December 31, 2016 Effective Interest Rate Cap Amount of Gain Recognized on Derivative Location of Gain Recognized in Income on Derivative Interest rate contracts $508 Other Comprehensive Income FAIR VALUE MEASUREMENTS – Assets and liabilities subject to fair value measurements are required to be disclosed within a fair value hierarchy. The fair value hierarchy ranks the quality and reliability of inputs used to determine fair value. Accordingly, assets and liabilities carried at, or permitted to be carried at, fair value are classified within the fair value hierarchy in one of the following categories based on the lowest level input that is significant to a fair value measurement: Level 1—Fair value is determined by using unadjusted quoted prices that are available in active markets for identical assets and liabilities. Level 2—Fair value is determined by using inputs other than Level 1 quoted prices that are directly or indirectly observable. Inputs can include quoted prices for similar assets and liabilities in active markets or quoted prices for identical assets and liabilities in inactive markets. Related inputs can also include those used in valuation or other pricing models such as interest rates and yield curves that can be corroborated by observable market data. Level 3—Fair value is determined by using inputs that are unobservable and not corroborated by market data. Use of these inputs involves significant and subjective judgment. The table below summarizes the estimated fair values of certain of our financial assets that are subject to fair value measurements, and the classification of these assets in our consolidated balance sheets, as follows (in thousands): As of December 31, 2018 Level 1 Level 2 Level 3 Total Current assets Interest Rate Contracts $ — $ 3,316 $ — $ 3,316 As of December 31, 2017 Level 1 Level 2 Level 3 Total Current liabilities Interest Rate Contracts $ — $ (595 ) $ — $ (595 ) The estimated fair value of these contracts was determined using Level 2 inputs. More specifically, the fair value was determined by calculating the value of the difference between t |